The term LONG-LASTING DOS refers to the Disk Operating System (DOS) developed by Microsoft in 1981. It was designed to be a long-lasting operating system that could be used on personal computers. The PERMS crossword solution is an acronym for Permanent Memory Storage, which is a type of memory storage that is non-volatile and can retain data even when the power is turned off. This type of memory storage was used in the original DOS system, allowing it to remain in use for many years.